There are many ways an eating disorder can take shape in the lives of different people, however, three major eating disorders affect the most people, so they get the lion's share of attention. They are anorexia nervosa (usually just called anorexia), bulimia nervosa (usually called bulimia), and binge eating disorder (BED).
Anorexia nervosa
Usually when people think of eating disorders, the first image that comes to mind is the emaciated face and body of the young woman with anorexia. Though actually the least prevalent of the major disorders — anorexia afflicts about 1 in every 100 people — it was the first to gain widespread public awareness. Anorexia also grabs attention because it's the most dangerous eating disorder. According to the Academy for Eating Disorders, the risk of death for a person with anorexia is 12 times higher than that of someone without an eating disorder.
A person with anorexia is terrified of becoming fat — so terrified that the fear rules everything she does. She believes she's always on the verge of fatness, regardless of her actual weight or what anyone else tells her. To guard against the dreaded outcome, she refuses to eat. The resulting weight loss can put her health and life in jeopardy. A person with anorexia may also purge like the people with bulimia, and/or she may exercise compulsively to help her control her weight.
Bulimia nervosa
You could most easily identify the person with bulimia by the behaviors of bingeing and purging — that is, if you could witness them. These behaviors are almost always done in secret. Bingeing is eating lots of food in one sitting — sometimes tens of thousands of calories — often rapidly. Purging is what the person with bulimia does to get rid of these calories. She may do this by vomiting what she's just eaten, overusing laxatives or diuretics, exercising excessively, or other methods.
After binge episodes, a person with bulimia feels extremely shamed and worthless. She's as preoccupied with avoiding fat as the person with anorexia. Also like the person with anorexia, she believes her weight determines her worth. Unlike the person with anorexia, however, chances are good that the person with bulimia is also dealing with alcohol or drug abuse and with depression. As many as 3 or 4 in 100 young women in the United States have bulimia nervosa.
Binge eating disorder (BED)
People with binge eating disorder (BED) binge pretty much like people with bulimia. And they feel just as bad afterward. But they aren't driven toward purging behaviors. More likely, they become engaged in cycling between periods of bingeing and periods of rigid dieting. For some, this keeps their weight in a normal range. Other people with BED gain weight and may even become obese.
Estimates are that anywhere from 3 to 8 in 100 people in the United States have BED. According to a 1998 survey in the Annals of Behavioral Medicine, as many as 40 percent of the people with BED are men.